Year	gross (GPI)
1970	0.903989970684052
1971	0.920059978961945
1972	0.928560018539429
1973	0.942120015621185
1974	0.963479995727539
1975	0.9826899766922
1976	0.990230023860931
1977	0.998539984226227
1978	1.0024299621582
1979	1.00476002693176
1980	0.996840000152588
1981	0.994170010089874
1982	0.998579978942871
1983	1.00591003894806
1984	0.999650001525879
1985	1.00578999519348
1986	1.00478994846344
1987	1.00739002227783
1988	1.00106000900269
1989	0.991840004920959
1990	0.987789988517761
1991	0.982710003852844
1992	1.00707995891571
1993	1.00911998748779
1994	1.01988005638123
1995	1.01678001880646
1996	1.02053999900818
1997	1.02257001399994
1998	1.03061997890472
1999	1.05048000812531
2000	1.06850004196167
2001	1.04147005081177
2002	1.04026997089386
2003	1.03474998474121
2004	1.03308999538422
2005	1.03771996498108
2006	1.04061996936798
2007	1.02391004562378
2008	1.02662003040314
2009	1.05178999900818
2010	1.03911995887756
2011	1.0401200056076
2012	1.05662000179291
2013	1.05685997009277
2014	1.06061005592346
2015	1.05533003807068
2016	1.05823004245758
2017	1.06231999397278
2018	1.06630003452301
2019	1.07005000114441
2020	1.07375001907349